mlxsw: spectrum_flower: Fix TOS matching

The TOS value was not extracted correctly. Fix it.

Fixes: 87996f91

 ("mlxsw: spectrum_flower: Add support for ip tos")
Reported-by: Alexander Petrovskiy <alexpe@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>